Sensory Mechanisms Related to Homing in Pigeons

Abstract

Besides having a well-developed vestibular system, pigeons possess a gravity and inertia sensitive system mediated by displacement of the viscera, presumed to stimulate mesenteric mechanoreceptors. Classical conditioning experiments confirm a sensitivity to atmospheric pressure changes. Failure to demonstrate a magnetic field orientation sensitivity in an instrumental conditioning situation is reported, Behavioral and physiological experiments establishing the pigeon’s ability to detect and orient itself with respect to an overhead polarized light are referred to. Failure to demonstrate discrimination of such a plane orientation on other experiments suggests that mechanisms connected with the upper field of vision are specialized for polarization plane detection. Evidence that pigeons can perceive and discriminate ultraviolet light is mentioned. Finally reference is made to the widespread forebrain projections of olfactory input.